what size is the tank? how much does it take to fill it up nornally from empty?
my m8 did this on his Transit put £20 of petrol into it,he filled the rest up £30 diesil and NO signs of the mishap,he drove it for the 1st 1/4 tank and refilled it done this twice and he was lucky no damage etc it's still going today and that was 4 yrs ago!
ps would be different if it was the other way though diesil into petrol cars IS empty tank etc